VAT Number Validation: Check EU Business Tax IDs in Seconds

What Is a VAT Number?

A VAT (Value Added Tax) number is a unique identifier assigned to businesses registered for VAT within the European Union. Also called a VAT registration number, it allows businesses to charge VAT on goods and services and reclaim VAT paid on business purchases.

Each EU country has its own VAT number format. For example, UK VAT numbers start with GB followed by 9 digits, while German numbers start with DE followed by 9 digits. The formats vary significantly in length, structure, and check digit algorithms.

How VAT Number Validation Works

VAT validation checks both the structural format and, optionally, the active registration status via official EU systems.

• Country prefix check — validates the two-letter country code matches a supported EU or UK VAT format
• Format validation — checks the number matches the expected pattern for that country including length and character types
• Check digit algorithm — many countries use modulus-based check digits that can be mathematically verified

When To Use VAT Validation

VAT validation is essential in B2B invoicing workflows where incorrect VAT numbers can lead to tax compliance issues.

• Invoice generation — validate customer VAT numbers before issuing invoices to ensure tax compliance
• E-commerce checkout — verify VAT numbers at checkout for B2B customers requesting VAT-exempt pricing
• Supplier onboarding — validate vendor VAT details during procurement setup to prevent fraudulent invoices

Frequently Asked Questions

Does VAT validation confirm a business is currently VAT registered?

Format validation confirms the structure is correct but cannot confirm active registration status. For live status verification, the EU's VIES (VAT Information Exchange System) provides real-time lookups of EU VAT registrations.

Can I validate VAT numbers from non-EU countries?

CheckTown supports EU VAT formats plus UK VAT numbers (post-Brexit). Other countries have their own tax identification systems with different names and formats — GST in Australia, EIN in the US, etc.

What happens if I issue an invoice with an invalid VAT number?

Invoices with incorrect VAT numbers can be rejected by tax authorities, leading to failed VAT reclaim, penalties, or audit issues. In some jurisdictions, you may also lose the right to charge VAT-exempt pricing to the business in question.